Relay Failure?
Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=64165
Printed Date: May 07, 2024 at 7:39 PM
Topic: Relay Failure?
Posted By: adrianspeeder
Subject: Relay Failure?
Date Posted: October 10, 2005 at 9:04 PM
I have a 12volt relay to trigger my air horns.
Well, when they didn't honk today I went to work with my meter and found that the two 87 terminals are grounded together, and neither connect to the common 30 terminal. Did they melt internally?
Also, should the two coil terminals 85 and 86 have zero resistance between them?
Adrianspeeder
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'02 F250 PSD, '97 F-150, '71 F-100, '66 F-250, '93, '92, '88, '84 Broncos
Penn State electrical engineerin' major
Replies:
Posted By: Ween
Date Posted: October 10, 2005 at 10:44 PM
hi, i'd say it's possible they melted. what is the current rating of the contacts of the relay? how much current does the compresser for the horns draw? yes there should be a resistance between the 85 and 86 terminals, say 80 to 120 ohms. hope this helps. mark
Posted By: adrianspeeder
Date Posted: October 11, 2005 at 7:20 AM
Howdy, thanks for the ohm values. It is a 30 amp relay, and I have the circuit fused at 20amps. No shorts, and it has been working fine for about a year now. Just prolly let loose, tryin to find out why today. Adrianspeeder ------------- '02 F250 PSD, '97 F-150, '71 F-100, '66 F-250, '93, '92, '88, '84 Broncos
Penn State electrical engineerin' major
Posted By: KPierson
Date Posted: October 16, 2005 at 12:16 AM
The contacts of the relay won't effect the coil of the relay, as they are isolated. Like said above, here should be resistance from 85 to 86. Have you tried measuring resistance with the relay completely unhooked? ------------- Kevin Pierson
Posted By: adrianspeeder
Date Posted: October 19, 2005 at 2:38 PM
Yup, I get zip across the coil. Bought another one and it all works fine. Anyone pop one of these apart?
Adrianspeeder
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'02 F250 PSD, '97 F-150, '71 F-100, '66 F-250, '93, '92, '88, '84 Broncos
Penn State electrical engineerin' major
Posted By: brendulc
Date Posted: November 27, 2005 at 5:27 PM
Try and measure the Amps drawn by the horns. It sounds like the horns are either drawing to much amps or the previous terminal connections was not a tight fit which caused arcing, which then caused heat and possible melting of the relay case, which in turn cause relay failure. ------------- Brendan R Botha
Posted By: 96hawkcnvt
Date Posted: November 28, 2005 at 11:31 PM
Could just go to a 50 amp (n.o.)relay in the same configuration for some insurance.
Todd
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